title: A correlation between the in vitro drug toxicity of drugs to cell lines that express human P450s and their propensity to cause liver injury in humans.
abstract: Drug toxicity to T-antigen-immortalized human liver epithelial (THLE) cells stably transfected with plasmid vectors that encoded human cytochrome P450s 1A2, 2C9, 2C19, 2D6, or 3A4, or an empty plasmid vector (THLE-Null), was investigated. An automated screening platform, which included 1% dimethyl sulfoxide (DMSO) vehicle, 2.7% bovine serum in the culture medium, and assessed 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium reduction, was used to evaluate the cytotoxicity of 103 drugs after 24h. Twenty-two drugs caused cytotoxicity to THLE-Null cells, with EC₅₀ ≤ 200 μM; 21 of these drugs (95%) have been reported to cause human liver injury. Eleven drugs exhibited lower EC₅₀ values in cells transfected with CYP3A4 (THLE-3A4 cells) than in THLE-Null cells; 10 of these drugs (91%) caused human liver injury. An additional 8 drugs, all of which caused human liver injury, exhibited potentiated THLE-3A4 cell toxicity when evaluated using a manual protocol that included 0.2% or 1% DMSO, but not bovine serum. Fourteen of the drugs that exhibited potentiated THLE-3A4 cell toxicity are known to be metabolized by P450s to reactive intermediates. These drugs included troglitazone, which was shown to undergo metabolic bioactivation and covalent binding to proteins in THLE-3A4 cells. A single drug (rimonabant) exhibited marked THLE cell toxicity but did not cause human liver injury; this drug had very low reported plasma exposure. These results indicate that evaluation of toxicity to THLE-Null and THLE-3A4 cell lines during drug discovery may aid selection of drugs with reduced propensity to cause drug-induced liver injury and that consideration of human exposure is required to enhance data interpretation.
authors.affiliation: * Global Safety Assessment and.
authors.forename: Frida
authors.initials: F
authors.lastname: Gustafsson
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Foster
authors.forename: Sunil
authors.initials: S
authors.lastname: Sarda
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Bridgland-Taylor
authors.forename: J Gerry
authors.initials: JG
authors.lastname: Kenna
mesh_terms: D001681:Biological Assay; D001711:Biotransformation; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D056486:Chemical and Drug Induced Liver Injury / Q000201:enzymology / Q000209:etiology* / Q000473:pathology; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D020128:Inhibitory Concentration 50; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D018570:Risk Assessment; D012307:Risk Factors; D018675:Toxicity Tests; D014162:Transfection
chemical_list: D003577:Cytochrome P-450 Enzyme System
keywords: CYP3A4-dependent bioactivation.; THLE cell lines; drug hepatotoxicity; in vitro toxicity